Auto injector with cartridge retention system

ABSTRACT

An auto injector ( 4 ) for administering injection of a medicament from a cartridge ( 700 ) containing the medicament, the auto injector comprising: a cartridge receiver ( 300 ) with a cartridge receiver compartment ( 302 ) configured to receive a cartridge assembly ( 600 ) with at least one cartridge retention member ( 808 ) when inserted through a cartridge receiver opening ( 302 ) along a longitudinal axis; and an ejector ( 200 ) configured to support the cartridge assembly ( 600 ) by being suspended to move along the longitudinal direction and being spring-loaded in the direction opposite of the receiving direction. The cartridge receiver compartment ( 302 ) has a first section ( 310 ), at a first distance from the cartridge receiver opening ( 301 ), with inwardly extending first guide members ( 312 ) that extends over first guide member angles ( 314 ) and are spaced apart to form a passage ( 316 ) at passage angles ( 318 ) between the inward first guide members ( 312 ); wherein the inward first guide members ( 312 ) form a first bore ( 320 ) accepting the cartridge assembly ( 600 ) when inserted through the cartridge receiver opening ( 301 ). The cartridge receiver compartment ( 302 ) has a second section ( 330 ) with an annular shape, at a second distance from the cartridge receiver opening ( 301 ), and with second guide members ( 322 ) with first faces ( 324 ) that are inclined about a radial axis to the longitudinal axis and angularly arranged to extend at least partly over the passage angles ( 318 ) and the first guide member angles ( 314 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application of PCTInternational Application Number PCT/EP2016/082856, filed on Dec. 29,2016, designating the United States of America and published in theEnglish language, which is an International Application of and claimsthe benefit of priority to European Patent Application No. 15203132.4,filed on Dec. 30, 2015, and European Patent Application No. 15203137.3,filed on Dec. 30, 2015. The disclosures of the above-referencedapplications are hereby expressly incorporated by reference in theirentireties.

The present invention generally relates to an auto-injector, which is anautomatic or semi-automatic drug delivery device adapted to receive adrug filled cartridge and expel a dose therefrom.

In the disclosure of the present invention reference is mostly made tothe treatment of Human Growth Hormone, HGH, however, this is only anexemplary use of the auto-injector.

The most common type of auto-injection devices adapted to receive a drugfilled cartridge (also termed reservoir or container) and expel a dosetherefrom are generally elongated e.g. pen-formed for being held in auser's one hand and utilizes a so-called cartridge holder adapted toreceive and mount a cartridge in the device. Correspondingly, mostpen-formed drug delivery devices comprise a generally cylindricalcartridge holder for receiving and holding a generally cylindricaldrug-filled cartridge in a mounted position, the cartridge comprising aproximally facing and axially displaceable piston, and a main body witha housing in which a drug expelling mechanism is arranged, the mechanismcomprising an axially displaceable piston rod adapted to engage thepiston of a mounted cartridge to thereby expel a dose of drug from thecartridge. Between the cartridge holder and the main body coupling meansis provided allowing a user to remove the cartridge holder from the mainbody and reattach it when a used cartridge has been exchanged with a newcartridge. The cartridge is inserted in the cartridge holder by axialmovement through a proximal opening. Conventionally, the coupling meansare in the form of a threaded connection or a bayonet coupling.

It is conventionally only insufficiently addressed that there is a needfor devices that are easier and more intuitive to use.

RELATED PRIOR ART

US 2014/358093 and in particular FIG. 6 therein discloses a drugdelivery system comprising a cartridge and a device with a front-loadedcartridge holder adapted to axially receive and hold a cartridge in aloaded position. The cartridge comprises first coupling means arrangedat the distal portion, and the cartridge holder comprises secondcoupling means arranged at the distal portion, wherein the first andsecond coupling means are configured to engage each other byfront-loading when the cartridge is inserted into the cartridge holderby an axial movement that is completed by an angular rotation.

U.S. Pat. No. 9,173,995 describes a front loaded device. Tapered lugsprotrudes radially from a syringe barrel that is front loaded into thedevice—and while the syringe barrel is inserted along a longitudinalaxis, the tapered lugs thereof are guided firstly be a first retainingring and secondly by a second retaining ring which is rotatable andspring loaded about the longitudinal axis. The first retaining ring hasprotrusions that are tapered to guide the tapered lugs between theprotrusions. At the point where the tapered lugs on the syringe barrelhave passed the first retaining ring, the second retaining ring, whichis rotatable and spring loaded about the longitudinal axis and whichalso has protrusions, engages with the tapered lugs of the syringebarrel to rotate the syringe barrel to a position where its tapered lugsare moved behind the protrusions of the first retaining ring. By thespring loading, the syringe barrel is kept in a fixed position. Thesyringe barrel is removed by turning it, thereby overcoming the springforce.

However, these front-loaded drug delivery systems are cumbersome to usesince they require that a user uses two hands for the operation ofloading the drug delivery system with a cartridge since one hand isneeded to hold the device and another is needed to insert and rotate thecartridge. For at least some groups of users this may preventself-administration use or make own use very cumbersome.

SUMMARY

There is provided an auto injector for administering injection of amedicament from a cartridge containing the medicament, the auto injectorcomprising:

-   -   a housing; and    -   a cartridge receiver with a cartridge receiver compartment        configured to receive a cartridge assembly with at least one        cartridge retention member when inserted through a cartridge        receiver opening along a longitudinal axis; and    -   an ejector configured to support the cartridge assembly by being        suspended to move along the longitudinal direction and being        spring-loaded in the direction opposite of the receiving        direction;        wherein the cartridge receiver compartment has a first section,        at a first distance from the cartridge receiver opening, with        inwardly extending first guide members that extends over first        guide member angles and are spaced apart to form a passage at        passage angles between the inward first guide members; wherein        the inward first guide members form a first bore accepting the        cartridge assembly when inserted through the cartridge receiver        opening;        wherein one or more of the first guide members has/have a face        that faces away from the cartridge receiver opening and forms a        concave shape with a slope portion, at slope angles, leading        towards a retention portion at or about a bottom portion of the        concave shape;        wherein the cartridge receiver compartment has a second section        with an annular shape, at a second distance from the cartridge        receiver opening, and with second guide members with first faces        that are inclined about a radial axis to the longitudinal axis        and angularly arranged to extend at least partly over passage        angles and protrusion angles;        wherein the second guide member has second faces that are        inclined about a radial axis to the longitudinal axis and are        arranged alternately with the first faces;        wherein the first faces and the second faces are inclined        towards greater distance from the cartridge receiver opening in        a direction of rotation being either a clockwise or        anticlockwise direction;        wherein the first faces and the second faces are separated by        first riser portions; and wherein the first riser portions are        angularly positioned at or within the first guide member angles.

Since the cartridge assembly has at least one cartridge retentionmember, retention of the cartridge retention member gives retention ofthe cartridge assembly and thus a cartridge accommodated in thecartridge assembly.

In this way intuitive front loading of an auto injector is enabled.Additional advantages are presented further below.

Retention is achieved in that when the cartridge assembly is inserted,at a first angular position, along the longitudinal axis, the cartridgeretention member travels with the cartridge assembly and via the passageit passes between the inwardly extending first guide members and onwardsuntil it lands on the inclined face of one of the second guide members,which by their inclined faces causes a rotation of the cartridgeretention member and thus the cartridge assembly from the first angularposition to a second angular position as the insertion continues atleast until the cartridge retention member has reached the first guidemember angles via the inclined face. The cartridge retention member isthus brought ‘behind’ the first guide members at the second angularposition, where the ejector, since it is spring-loaded, presses thecartridge retention member in a direction opposite of inserting thecartridge assembly and against an underside of the first guide members,wherein the underside is a side facing away from the cartridge receiveropening. In this way the cartridge assembly is retained in the cartridgereceiver compartment.

The cartridge assembly is typically inserted by a human being insertingthe cartridge assembly with a force sufficient to overcome thespring-load acting on the cartridge assembly. At the second angularposition the human being may ease the force applied to overcome thespring-load, whereby the spring-load moves the cartridge assemblyoutwards, but at an angular position where the cartridge retentionmember and the underside of first guide members restrict the outwardmovement such that the cartridge assembly is prevented from falling out.

The first section may be arranged closer to the cartridge receiveropening than the second section. The first section and the secondsection are spaced apart in the longitudinal direction by a clearanceexceeding the longitudinal extent of the cartridge retention member suchthat rotation of the cartridge assembly about the longitudinal axis ispossible at least for some longitudinal positions of the cartridgeassembly relative to the first and second sections.

In some aspects the spring-load acting on the cartridge assembly isexercised directly or indirectly by a resilient member such as a spiralspring also known as a helical spring.

In some aspects the cartridge assembly, when disregarding the cartridgeretention members, is substantially circular. The cartridge receivercompartment may have a substantially round interior.

In some aspects the first bore of the first section is circular orsubstantially circular. There may be six pairs of a first guide memberand a passage annularly arranged about the bore. Pairs of a first guidemember and a passage may cover an angle range of e.g. about 60 degrees.In some aspects there are 4, 5, 7 or 8 pairs of a first guide member anda passage. In some aspects the passage covers an angular range of about15 degrees and the first guide member covers an angular range of about45 degrees.

The concave shape of the first guide members serve to improve rotationalretention of the cartridge assembly when the ejector exercises thespring-load on the cartridge assembly. The cartridge assembly retentionmember then lands in the concave shape and is retained by the ‘slopes’of the concave shape.

The slope portion may be defined by a face inclined towards theinsertion opening for a direction of rotation and in the direction ofrotation leading towards the deepest point of the concave shape.

The concave shape may be asymmetric about a centre line in thelongitudinal direction. The slope portion may comprise a substantiallyflat portion that is inclined to smoothly rotate the cartridge retentionmember upon a move along the longitudinal axis, in a direction oppositeof insertion, towards the retention angle. The retention portion may ina clockwise or anticlockwise rotation about the longitudinal direction,coherently continue from the slope portion and terminate in a retentionface where the cartridge retention member is prevented from furthersmooth rotation. The retention face may be substantially parallel to thelongitudinal axis.

To achieve a desired rotational retention of the cartridge assembly,depth and steepness of the concave shape may be adapted to the shape ofthe cartridge assembly or vice versa. In some aspects the concave shapeis deeper than the radius of a circle circumscribing an end portion ofthe cartridge retention member.

The at least one of the first faces serves to rotate a cartridgeretention member that lands on the first face, upon its travel throughthe passage, to an angular retention position behind the first guidemember i.e. at a first guide member angle; whereas a second face next tothe first face serve to further rotate the cartridge retention member,travelling on an outbound journey, from the angular retention positionto or towards a passage on the other side of the first guide member thatheld it in a retention position after its inbound journey. Thus thecartridge retention member is rotated monotonously in the direction ofrotation.

In embodiments wherein one or more of the first guide members has/have aface that faces away from the cartridge receiver opening and forms aconcave shape with a retention portion at a retention angle about thelongitudinal axis and a slope portion at slope angles about thelongitudinal axis, at least one of the first faces serves to rotate acartridge retention member that lands on the first face, upon its travelthrough the passage, to or towards guide angles of the first guidemembers. The second faces serve to rotate the cartridge retentionmember, travelling on an outbound journey, from the retention angle toor towards a passage on the other side of the first guide member thatheld it in a retention position. The guide portion of the first memberserves to make the cartridge retention member pass the riser portionseparating the first faces and the second faces.

Due to the inclined faces and the riser portions separating them anannular saw-tooth-like shape is provided. In some aspects the riserportions are substantially parallel to the longitudinal axis. In someaspects the riser portions have substantially the same height.

In some embodiments, the first guide members have a first guide facethat faces the cartridge receiver opening and forms a convex pointingshape with an apex directed towards the cartridge receiver opening.

Thereby insertion of the cartridge assembly can start out at any angularposition about the longitudinal axis or at least at a wider selection ofangles without the cartridge retention members being obstructed by thefirst guide members and thus prevent the cartridge assembly from furtherlongitudinal movement in the insertion direction.

In case the angular position is such that the cartridge retentionmembers do not align with the passages when the insertion of thecartridge assembly starts out, the cartridge retention members and thusthe cartridge assembly smoothly proceed by an angular rotation caused bythe pointing shape of the first guide members. This improves the ease ofuse of the auto-injector also for those with below average motoricskills.

In some aspects the apex has an angle of about 90 degrees, e.g. 70-110degrees. In some aspects the apex is symmetrically positioned withrespect to the angular extent, about the longitudinal axis, of the firstguide member; however, it may alternatively be asymmetricallypositioned.

In some embodiments, the first section and the second section maintainsa fixed angular position with respect to each other. Thereby the passagebetween the inward first guide members and the guide members remain in afixed position with respect to the first faces and the second faces.This in turn secures that the one or more cartridge retention members,of the cartridge assembly, are always guided in the same way. Thisimproves the quality of the user's experience of the auto injector.

In some embodiments, one or more of the first guide members has/have aface that faces away from the cartridge receiver opening and forms aconcave shape with a guide portion, at slope angles, leading towards aretention portion at or about a retention angle at or about a bottom ofthe concave shape; wherein one or more first riser portions areangularly arranged at slope angles; and wherein one or more first riserportions are angularly arranged between the retention angle and a centreof passage angles in a direction of rotation being either a clockwise oranticlockwise direction.

The riser portions, in cooperation with the slope portion of the concaveshape, enables at least partially that a first movement overcoming thespring-load in an insertion direction leads to retention of thecartridge assembly, whereas a second movement in the same direction,also overcoming the spring-load, leads to a release of the cartridgeassembly.

The retention angle may be defined by the bottom of the concave shape.The guide portion may be defined by a face inclined towards theinsertion opening for a direction of rotation and in the direction ofrotation leading towards the bottom of the concave shape.

The direction of rotation is defined as the either a clockwise oranticlockwise direction in which the first faces are inclined towardsgreater distance from the cartridge receiver opening.

In some embodiments, one or more of the first faces and the second facesare divided into sections separated by a second riser portion. Such afurther riser portion hinders at least to some extend an unintendedreverse rotation when the at least one cartridge retention membertravels on the first face and second face on an inbound journey.

When the at least one cartridge retention member travels, clockwise oranticlockwise about the longitudinal axis, on the first face on aninbound journey, the first riser portions prevent the cartridgeretention member from a further rotation in the respective direction. Onthe contrary, the second riser portions hinder an unintended reverserotation to the respective rotational direction. In some aspects thefirst riser portions are higher than the second riser portions.

In some embodiments, the first guiding member has an eject face that isinclined towards the cartridge receiver opening at angles beyond theretention angle in a direction of rotation being either a clockwise oranticlockwise direction. Thereby it is possible that any passage amongthe passages formed between the first guide members can be used forinsertion leading to retention. Upon a release operation, the eject faceguides the cartridge retention member to a neighbouring passagefollowing in a direction of rotation.

In some embodiments, the second guiding members are configured as afirst set of steps with treads that are inclined about the radial axisand a second set of steps with treads that are inclined about the radialaxis; wherein the treads of the first and second steps are inclinedtowards greater distance from the cartridge receiver opening for aclockwise or anticlockwise direction of rotation; wherein the treads ofthe first set of steps are arranged more proximal to the cartridgereceiver opening than the treads of the second set of steps; and whereinthe first set of steps are alternately arranged with the second set ofsteps; with riser portions between the steps, forming an annular membercomprised by the second section.

When a cartridge retention member lands on a tread it is guideddownwards, in the insertion direction, on the inclined tread it landedon towards a neighbouring inclined step out over a riser portion betweenthe steps. The riser portion prevents or at least reduces the risk thata direction of rotation is suddenly reversed during insertion of thecartridge assembly whereby retention may fail and lead to anunsatisfactory user experience.

The treads of the first steps may be angularly arranged as the firstfaces mentioned above to extend at least partly over passage angles andprotrusion angles. In some aspects the treads of the first steps areangularly arranged to extend fully over passage angles. In some aspectsthe treads of the second steps are angularly arranged within protrusionangles.

In some aspects the steps are arranged such that two, three or fourtreads extend angularly over the same angles about the longitudinal axisas one passage and a neighbouring one first guide member.

In some embodiments, the first guide members and the second guidemembers are configured and angularly aligned such that: upon insertion,the cartridge retention member passes the passage in a longitudinaldirection, lands on a first section of the first face, by rotationfollows the first face out over a second riser portion to a secondsection, and upon ease of an insertion force: the cartridge retentionmember travels to the retention portion via the slope portion.

In some embodiments, the first guide members and the second guidemembers are configured and angularly aligned such that: upon release,e.g. by a user exerting a force, e.g. by pushing, on the cartridge inthe direction of insertion, the cartridge retention member leaves theretention position and lands on the first section of the second face, byrotation follows the second face out over a second riser portion to asecond section; and upon ease of the force: the cartridge retentionmember travels to the eject face, wherefrom a the cartridge retentionmember is guided towards the cartridge receiver opening via a passage.

In some embodiments, the ejector comprises an ejector lock that isoperative by one or more of rotation, translational movement and axialmovement to move to a position where movement of the ejector isrestricted in the direction of insertion. The ejector lock may therebylock the ejector to prevent it from moving backwards (i.e. in theinsertion direction) when the cartridge assembly has been inserted andis in a retention position that prevents it from moving forward (i.e.opposite direction of insertion). Thus despite the front loadedinsertion, the cartridge is prevented from moving backwards or forwardswhen locked as mentioned.

In some embodiments the ejector is configured with: an ejector supportface for supporting the cartridge or cartridge assembly, a longitudinalejector slot extending towards the ejector support face from an ejectorrest portion; and an ejector lock supported for turning at least afraction of a revolution and maintained in a longitudinal position, suchas a fixed longitudinal position, relative to the housing; wherein theejector lock has a ejector lock support portion that is configured toalign with and slide along the longitudinal ejector slot at a firstangle and to be brought to align with the ejector rest portion at asecond angle.

Thereby the ejector rest portion and the ejector lock support member incombination may form a stop that is disengaged at the first angle andengaged at the second angle.

Thus, it is appreciated that, at the second angle, the ejector lock byits turning effectively introduces a stop, by its support memberreceiving the rest portion. The stop prevents further movement of therest portion beyond the support member in the receiving direction, ifthe rest portion is not otherwise prevented from landing on the supportmember. Thus, the stop contributes to prevent the cartridge frommovement beyond a stop position, relative to the housing, in thereceiving direction.

At least when the needle of the cartridge assembly penetrates a being'sskin a force is transferred from the needle to the cartridge and worksto push the cartridge backwards in the receiving direction against thestop when it is engaged. The stop at least contributes to maintainingthe position of the cartridge since otherwise precise dose administeringmay be obstructed.

When the ejector, by means of the stop, sits at the stop position, itsejector support face supports that an end portion of the cartridge orcartridge assembly rests thereon to prevent unintended movement in thereceiving direction.

The auto injector enables convenient front-loading of a cartridgeaccommodated in a cartridge assembly. Since the needle on the cartridgeassembly may be protected by a needle cover reliably attached to thecartridge assembly, there is no increased risk of being injured by theneedle while loading the auto injector with a cartridge accommodated ina cartridge assembly.

The auto injector enables convenient front-loading by: overcoming thespring-loaded bias when the cartridge meets the support face of theejector, guiding the cartridge retention members from the passage to aposition where the cartridge is prevented from moving out of thecartridge receiver, and turning the ejector lock to prevent movementbeyond the stop in the receiving direction such that the cartridgemaintains its position in the housing when a pressure on the needle inthe receiving direction is at least partially transferred to thecartridge. It is important that the cartridge maintains its positionsince otherwise precise dose administering is obstructed.

It is appreciated that various distances should be dimensioned such thatthe support face of the ejector lock abuts the rest portion of theejector when the cartridge sits in the retention position. Thereby thecartridge is locked or is in a locked position being prevented both froma forward movement and a backward movement, wherein the backwardmovement is the same as the receiving direction. The cartridge is lockedwhen the stop is engaged i.e. when the ejector lock is at the secondangle, whereas the cartridge is unlocked when the stop is disengagedi.e. when the ejector lock is at the first angle.

In some aspects the ejector lock support member extends axially from awall of the ejector lock, e.g. in the form of a pin, to support theejector at a transversely extending ejector rest portion. In someaspects the ejector lock support member extends transversely along a rimor edge of the ejector lock to support the ejector at transverselyextending ejector rest portion or at an axially extending rest portion.

In some aspects one or more of the ejector lock support portion, theejector rest portion and the ejector slot are recessed into the ejectorlock or the ejector.

It is appreciated that the ejector lock is supported e.g. in a bearingthat allows the lock to turn or be turned, at least a fraction of arevolution, while preventing a longitudinal movement.

In some embodiments, the ejector comprises an ejector rod configuredwith one or more ejector cut-outs to form one or more ejector cogsbetween the ejector cut-outs; and wherein the ejector lock is configuredwith one or more ejector lock cogs between one or more ejector lockcut-outs, respectively.

Thereby the one or more ejector cogs may abut with the one or moreejector lock cogs to form the stop when engaged. The stop is engaged byaligning the cogs of the ejector and the ejector lock. Turning of theejector lock at least a portion of a revolution about the longitudinalaxis may disengage the stop whereby the ejector cogs can be accumulatedin the ejector lock cut-outs. In this way the cogs and the cut-outs formcomplementary cogs and cut-outs.

The one or more cogs of the ejector rod and the one or morecomplementary cut-outs of the ejector lock are arranged at angularranges about the longitudinal axis such that a cog can be accommodatedin its entirety or partially by a complementary cut-out. A cog mayextend over e.g. 45 degrees and a complementary cut-out may extend over45 degrees plus an angular range to allow a clearance when the ejectorrod and thus the cog moves in the longitudinal direction in or out ofthe cut-out of the ejector lock.

The angles at which cut-outs, cogs and complementary cogs and cut-outsare located implicitly define the first angular position where theejector lock and ejector rod mutually are angularly positioned to allowmovement of the cartridge assembly in the receiving direction, and thesecond angular position where the ejector lock and ejector rod mutuallyare angularly positioned to restrict movement of the cartridge assemblyin the receiving direction at least restricted from moving beyond apredefined longitudinal position.

In the second angular position, at least one cog of the ejector rodabuts end-to-end at least one cog of the ejector lock; whereas in thefirst angular position, the at least one cog of the ejector rod isaccommodated in a complementary cut-out.

The ejector cogs have end portions denoted an ejector rest portion andthe ejector lock cogs have end portions denoted an ejector lock supportportion.

The ejector lock support portion supports the ejector rest portion whenthe stop is engaged.

Thus the cogs have respective end portions which abut one another whenthe stop is engaged. Cut-outs of the ejector rod and cut-outs of theejector lock have respective bottom portions. The bottom portions mayextend between side portions separating cogs and cut-outs.

At a longitudinal position of the ejector rod where the cogs abut oneanother, the ejector defines by its length relative to the ejector lockat which position the cartridge or cartridge assembly is restricted fromfurther movement by means of the stop in the receiving direction. Theejector may be suspended by a resilient member to move in the oppositedirection of the receiving direction, in which case the cogs of theejector rod travels away from the cogs of the ejector lock.

In some aspects the ejector rod has four cogs and four cut-outs and theejector lock has four complementary cogs and four complementarycut-outs.

This gives a good trade-off between the amount of rotation needed toturn the ejector rod and the ejector lock relative to each other from asecurely locked position to an open position and mechanical robustnessof the cogs.

In some aspects the cogs and cut-outs have an even angular size, e.g. 45degrees or 60 degrees—in both cases minus an angular range to allow aclearance between a cog and a cut-out.

In some embodiments, one or more of the cut-outs and the cogs have asubstantially rectangular shape.

Thus, the one or more cut-outs, such as ejector cut-outs and/or ejectorlock cut-outs have edges orthogonal to the longitudinal axis and edgesalong the longitudinal axis. Due to the edges along the longitudinalaxis a good engagement for retaining a relative angular position betweenthe ejector rod and the lock is obtainable at least when the stop isengaged.

In some aspects thereof the ejector cut-outs accommodate ejector lockcogs and ejector lock cut-outs accommodate ejector cogs in acomplementary manner such that spaces are substantially filled outbetween cogs to resemble a cylindrical object. However, an angularclearance is typically needed between cogs to allow sufficiently lowfriction of a longitudinal movement and to allow for variationsoccurring during manufacture of the ejector and ejector lock.

In some embodiments the auto injector comprises a plunger rod operativeby movement along the longitudinal axis to exercise a pressing force ona cartridge accommodated in the cartridge assembly. The plunger rod maybe configured to move a first stopper of the cartridge to expel at leasta part of the medicament from the cartridge.

In some embodiments the plunger rod is accommodated in the ejector to belongitudinally displaceable. Thereby the ejector may support thecartridge along a rim thereof, whereas the plunger rod may actuatemovement of the first stopper of the cartridge to expel at least a partof the medicament from the cartridge.

In some embodiments the ejector lock comprises an ejector lock guide pinconfigured to engage with a plunger rod track provided in the plungerrod, such that longitudinal movement of the plunger rod, at least over apredefined range, inflicts a turning of the ejector lock about thelongitudinal axis.

In some embodiments the plunger rod track comprises at least one trackportion that guides the ejector lock guide pin from a first angle to asecond to turn an ejector lock from the first angular position to thesecond angular position.

In some embodiments the auto injector comprises an operational moduleconfigured to: engage the plunger rod to move along the longitudinalaxis to exercise a pressing force on a cartridge accommodated in thecartridge assembly; and engage an ejector lock by one or more ofrotation, translational movement and axial movement to move to aposition where movement of the ejector is restricted in the direction ofinsertion.

Thereby a human being may insert and remove a cartridge assemblymanually by two respective but very similar movements one after theother, before and after injection of a medicament contained in thecartridge carried in the cartridge assembly. Once inserted, automatic ormanual activation of the operational module may trigger automaticengagement of the ejector lock and the plunger rod to assist the humanbeing in injecting his/hers medicament. An operational module maycomprise one or more electric motors that engage the plunger rod and theejector lock.

BRIEF DESCRIPTION OF THE FIGURES

A more detailed description follows below with reference to the drawing,in which:

FIG. 1 shows an auto injector;

FIG. 2 shows the auto injector with a cartridge;

FIG. 3 shows a cartridge;

FIG. 4 shows a cartridge holder with a cartridge;

FIG. 5 shows a cross section of a cartridge assembly with a needleassembly;

FIG. 6 shows a cartridge receiver;

FIG. 7 shows the cartridge receiver with an ejector;

FIG. 8a shows a detailed view of the first section and second section ofthe cartridge receiver compartment; and FIG. 8b shows an inbound journeyand an outbound journey of a cartridge retention member;

FIG. 9a and FIG. 9b are cross-sectional views of the first section andsecond section of the cartridge receiver compartment;

FIG. 10 shows a detailed view of alternative first section and secondsection of the cartridge receiver compartment;

FIG. 11 shows an outer plunger rod;

FIG. 12 shows an ejector;

FIG. 13 shows an ejector lock;

FIG. 14a through 14d shows various positions of the ejector relative tothe ejector lock;

FIG. 15 shows a cross section of an exemplary system comprising an autoinjector and a cartridge assembly;

FIGS. 16a-d show cross sections of a portion of an exemplary systemcomprising an auto injector and a cartridge assembly; and

FIG. 17a-b show shows various positions of the ejector relative to theejector lock in an embodiment where the cogs have inclined faces.

DETAILED DESCRIPTION

Various embodiments are described hereinafter with reference to thefigures. Like reference numerals refer to like elements throughout. Likeelements will, thus, not be described in detail with respect to thedescription of each figure. It should also be noted that the figures areonly intended to facilitate the description of the embodiments. They arenot intended as an exhaustive description of the claimed invention or asa limitation on the scope of the claimed invention. In addition, anillustrated embodiment needs not have all the aspects or advantagesshown. An aspect or an advantage described in conjunction with aparticular embodiment is not necessarily limited to that embodiment andcan be practiced in any other embodiments even if not so illustrated, orif not so explicitly described.

The term ‘user’ refers to a human being using the auto injector forself-administering a medicament. In this respect the user may also bedesignated a ‘patient’. Thus, one use case of the auto injector isself-administration of a medicament. The auto injector is described withthis use case in mind. However, in another use case an assistant, e.g. anurse or home carer, may operate the auto injector to administer themedicament into the patient. The latter use case is also enabled by thepresent disclosure of the auto injector. The user may use the autoinjector in connection with his or hers daily activities.

FIG. 1 shows an auto injector. The auto injector 4 may be configured foradministering a medicament. The auto injector 4 may be an electronicauto injector.

The auto injector 4 comprises a housing 6. The auto injector 4 comprisesa cartridge receiver 300. The cartridge receiver is configured toreceive a cartridge and/or a cartridge assembly comprising a cartridge.The cartridge may contain the medicament.

The cartridge receiver 300 has a cartridge receiver opening 301. Thecartridge receiver 300 is configured to receive the cartridge and/or thecartridge assembly through the cartridge receiver opening 301 in acartridge receiving direction 304 along a longitudinal axis, L.

The auto injector 4 may comprise a user interface 1100, as illustrated.The auto injector 4 comprises a trigger member, such as the contactmember 1102. The contact member 1102 may be configured to be pressedagainst an injection site on a patient's skin. The contact member 1102may be movable in the cartridge receiving direction 304, relative to thehousing, if pressed against the injection site. The contact member 1102may be part of the user interface 1100.

The user interface 1100 comprises a first input member 1108, e.g. abutton. The first input member 1108 may provide for a user input from auser. For example, the first input member 1108 may be used for receivinga push from a user to proceed to a next step.

The user interface 1100 comprises a first output member 1110 asillustrated, e.g. a plurality of LEDs. The first output member 1110 mayprovide for a user output to a user. The user interface 1100 maycomprise a second output member (not shown), e.g. a speaker. The secondoutput member may be configured to provide audible output to the user.For example, the first output member 1110 and/or the second outputmember may be used to indicate a step in the procedure to the userand/or to indicate an error message.

The auto injector 4 may comprise a cover (not shown) to protect the autoinjector from dirt and filth when not in use.

FIG. 2 shows the auto injector with a cartridge. The system 2 comprisesan auto injector 4, as described in relation to FIG. 1, and an exemplarycartridge 700 received in the cartridge receiver 300 by front loading.The cartridge 700 is shown with a needle cover 908. The needle cover 908extends out of the contact member 1102 to allow removal of the needlecover 908 from the cartridge 700.

By front loading is understood that at least the cartridge 700 isreceived with its needle end pointing out of the cartridge receiveropening 301. When the cartridge is being inserted and especially when itis fully inserted or almost fully inserted, the cartridge or cartridgeassembly may be substantially covered by the housing or the contactmember 1102. Especially in this situation the needle cover 908 serves asa protective means that makes it possible for a user at least to presson the needle cover 908 or a tip thereof to fully insert the cartridgewithout being injured by the needle. When the cartridge is fullyinserted and sits in a retention position it is possible to detach theneedle cover such that the auto injector is ready for use to inject themedicament or a portion thereof contained in the cartridge. After use,i.e. when a dose of medicament has been injected, the needle cover isattached such that the needle cover again serves as a protective meansthat makes it possible for a user at least to press on the needle cover908 or a tip thereof to remove the cartridge without being injured bythe needle.

FIG. 3 shows a cartridge, such as a cartridge 700 being configured to bereceived in the cartridge receiver of an auto injector, such as the autoinjector described in relation to the preceding figures.

The cartridge 700 comprises a cartridge compartment 702. The cartridgecompartment 702 may be configured for containing a medicament. Thecartridge 700 has a first end 718 and a second end 720. The cartridge700 comprises a cartridge outlet 714 at the first cartridge end 718. Thecartridge may be configured to expel medicament through the cartridgeoutlet 714. The cartridge outlet 714 may be sealed by a needlepenetrable sealing. The sealing may be made from rubber and optionallycomprise a piercing which enables the needle to penetrate the sealing,while sealing the medicament when the needle is not penetrating thesealing.

The cartridge comprises a first stopper 708 movable inside the cartridgecompartment, e.g. in a first stopper direction 722, e.g. towards thefirst cartridge end. For example, the medicament may be expelled throughthe cartridge outlet 714 upon movement of the first stopper 708 in thefirst stopper direction. The cartridge comprises a cartridge back face716 at the second cartridge end. The cartridge back face 716 comprises acartridge back end opening for providing access to the first stopper 708for a plunger rod.

As illustrated, the cartridge 700 may be a dual chamber cartridge. Thecartridge comprises a second stopper 710 movable inside the cartridgecompartment 702, e.g. in the first stopper direction 722, e.g. towardsthe first cartridge end. The cartridge compartment 702 comprises a firstcartridge sub-compartment 704 and a second cartridge sub-compartment706. The first cartridge sub-compartment 704 is between the firststopper 708 and the second stopper 710. The second cartridgesub-compartment 706 is between the second stopper 710 and the cartridgeoutlet 714. The cartridge comprises a bypass section 712 for providingfluid communication between the first cartridge sub-compartment and thesecond cartridge sub-compartment. The bypass section 712 provides fluidcommunication between the first cartridge sub-compartment and the secondcartridge sub-compartment when the second stopper 710 is positioned inthe bypass section 712.

The first cartridge sub-compartment 704 contains a first medicamentcomponent 792 of the medicament 790. The first medicament component 792may be a liquid as illustrated. The second cartridge sub-compartment 706contains a second medicament component 794 of the medicament 790. Thesecond medicament component 794 may be a powder composition. Bypositioning of the second stopper 710 within the bypass section 712, thefirst medicament component 792 may be transmitted into the secondcartridge sub-compartment 706 via the bypass section 712, thereby mixingthe first medicament component 792 and the second medicament component794 to achieve the combined medicament 790.

The cartridge 700 may generally have a cylindrical form. However, theby-pass section 712 may form a protrusion from the generally cylindricalform.

FIG. 4 shows a cartridge holder with a cartridge. The cartridge holder800 accommodates at least a portion of the cartridge 700 by frictionalcoupling. Like the cartridge 700, the cartridge holder 800 may have agenerally cylindrical form. An inner diameter of the cartridge holder800 matches with an outer diameter of the cartridge. The cartridgeholder may be made from a plastics material, whereas the cartridgetypically is made from glass or a glass-like material; the cartridge mayalso be made from a plastics material.

As shown, the cartridge holder 800 accommodates the first cartridge end718 of the cartridge. The cartridge holder 800 has a cartridge holderslot 814 which accommodates the by-pass section 712 which is shown inFIG. 3 as a protruding member. The cartridge holder introduces couplingoptions to the cartridge in the form of a needle assembly couplingportion 812, which as shown may take the form of a threading, andcartridge retention members 808. The cartridge retention members 808 maytake the form of protrusions that extends from the generally cylindricalform of the cartridge holder 800. The cartridge retention members 808may be located at or close to the rim of the cartridge holder at theopposite end of the cartridge assembly outlet opening 806. In someembodiments the cartridge retention members 808 are arranged at agreater distance from the rim than shown.

The needle assembly coupling portion 812 makes it possible to couple thecartridge 700, via the cartridge holder 800, to a needle assembly aswill be described in greater detail below.

FIG. 5 shows a cross section of a cartridge assembly with a needleassembly. Note that the cartridge 700 is shown without stoppers, butwith the by-pass section 712.

The needle assembly 900 is coupled to the cartridge holder by arespective needle assembly coupling portion 812 and cartridge holdercoupling portion 906 of the needle assembly and the cartridge holder.The coupling portions 812 and 906 may be in the form of threading.

The needle assembly 900 comprises a needle hub 904 that holds a needle902. The needle hub 904 may have a bore at its one end into which theneedle extends and on sidewalls of which the needle assembly couplingportion 812 is arranged. The needle assembly 900 also comprises a needlecover 908 that may be coupled by frictional coupling to the needle hub.

FIG. 6 shows a cartridge receiver. The cartridge receiver 300 has acartridge receiver compartment 302 configured to receive a cartridgeassembly 600 through a cartridge receiver opening 301. The cartridgereceiver compartment 302 has a first section, at a first distance fromthe cartridge receiver opening 301, with inwardly extending first guidemembers 312 that are spaced apart to form passages 316 between theinwardly extending first guide members 312. The inwardly extending firstguide members 312 form a first bore accepting the cartridge assembly 600when inserted through the cartridge receiver opening 301. The diameterof the bore is slightly larger than an outer diameter of the cartridgeassembly 600 excluding the cartridge retention members 808, but issmaller than the diameter of a circle circumscribing the cross sectionof the cartridge assembly 600 and the cartridge retention members 808.The cartridge retention members 808 can thereby not pass a first guidemember 312 unless the cartridge is turned about the longitudinal axis,L, such that the cartridge retention members pass through the passages316.

The cartridge receiver compartment 302 has an additional second section,with an annular shape, at a second distance, more remote than the firstdistance, from the cartridge receiver opening 301. The second sectionhas second guide members 322. The second guide members 322 are arrangedwith inclined faces and at angular positions about the longitudinal axissuch that a cartridge retention member 808 having passed the passage 316next to a first guide member 312 in the receiving direction is guidedbehind the first guide member 312 by an angular turning about thelongitudinal axis, L.

The second guide members 322 form a second bore also accepting thecartridge assembly 600. The diameter of the second bore is substantiallythe same as the first bore, i.e. slightly larger than an outer diameterof the cartridge assembly 600 excluding the cartridge retention members808, but smaller than the diameter of a circle circumscribing the crosssection of the cartridge assembly 600 and the cartridge retentionmembers 808. The cartridge retention members 808 can thereby not pass asecond guide member 322. So when a cartridge retention member 808 landson the second guide members 322, a turning of the cartridge assembly isinflicted.

The cartridge receiver 300 comprises flanges and coupling means such asopening 352 for coupling to other components of the auto injector (notshown). The cartridge receiver 300 also comprises a base 354 comprisinga bore 356 for a spring (not shown) providing a spring-bias to thecontact member 1102, which may be guided by a guide rod (not shown)accommodated in a bore 350.

FIG. 7 shows the cartridge receiver with an ejector. In this view thecartridge receiver 300 is shown in a different perspective than in FIG.6. It is shown that an ejector 200 extends out of the cartridge receiver300 from the other end of the cartridge receiver than the cartridgereceiver opening end.

FIG. 8a shows a detailed view of the first section and the secondsection of the cartridge receiver compartment. In this view, portions ofthe first section 310 and the second section 330 are cut up along thelongitudinal axis and fold out from their generally annular shape. Thefunctional aspects of the first section and the second section aredescribed in connection with FIG. 8b below. The dashed line at thebottom of FIG. 8a indicates the orientation of the longitudinal axis, L,and points in the receiving direction, which in this depiction is to theleft. The cartridge receiver opening (not shown in this depiction) islocated towards the right hand side. Thus, the first section 310 isarranged closer to the cartridge receiver opening than the secondsection 330. The curved dashed line to the left, DR, indicates adirection of rotation about the longitudinal axis when the first section310 and the second section 330 are arranged as annular members.

The first section 310 comprises first guide members 312 and the secondsection 330 comprises second guide members 322.

The first guide members 312 extends over first guide member angles 314and are spaced apart to form passages 316 at passage angles 318 betweenthe first guide members 312.

The second guide members 322 have first faces 324 and second faces 326(cf. FIG. 10). The first faces and the second faces are arrangedalternately and separated by first riser portions 340. The first facesare, in the exemplary embodiment of FIG. 8a , divided into sections 344and 346 separated by a second riser portion 342. Similarly, the secondfaces are, in the exemplary embodiment of FIG. 8a , divided intosections 344 and 346 separated by second riser portions 342. The firstfaces are inclined about a radial axis to the longitudinal axis andangularly arranged to extend at least partly over passage angles 318 andfirst guide member angles 314.

The first guide members 312 have a first guide face that faces thecartridge receiver opening, i.e. to the right hand side in thisdepiction, and forms a convex pointing shape with an apex directedtowards the cartridge receiver opening.

The first guide members 312 also have a face that faces away from thecartridge receiver opening, i.e. to the left hand side in thisdepiction, and forms a concave shape with a slope portion 334, at slopeangles 336, leading towards a retention portion 328 at or about a bottomportion of the concave shape at a retention angle 332. The slope portion334 is inclined relative to the longitudinal axis and relative to theorthogonal thereto such that a turning of the cartridge is inflictedwhen a cartridge retention member 808 is pushed towards the slopeportion 334 by a spring-loaded ejector 200. The turning brings thecartridge retention member 808 to the retention portion 328. To limitfurther turning of the cartridge assembly, a retention face 348 isprovided substantially along the longitudinal axis.

Further, the first guide members 312 also have an eject face 338 with aslope that is inclined relative to the longitudinal axis and relative tothe orthogonal thereto such that a turning of the cartridge is inflictedwhen a cartridge retention member 808 is pushed towards the slopeportion 338 by a spring-loaded ejector 200.

FIG. 8b shows an inbound journey and an outbound journey of a cartridgeretention member. The cartridge retention member 808 is depicted as anobject with a circular cross section, e.g. in the form of a guide pin,but it may have other forms. The cartridge retention member 808 is shownat different positions indexed by a numeral following the referencenumeral; for instance 808-1 indicates the position of the cartridgeretention member 808 at position 1.

Dashed lines indicate a so-called inbound journey of the cartridgeretention member 808 and dashed-dotted lines indicate a so-calledoutbound journey. To avoid cluttering the figure, not all referencenumerals are inserted, however the reference numerals used in FIG. 8aapply to FIG. 8b for like-shaped elements.

When a cartridge assembly 600 with a cartridge retention member 808 isinserted, starting out in the receiving direction, the cartridgeretention member 808 follows an inbound journey. As examples the inboundjourney may start at position 1 or position 2 or position 3 at differentangles. At position 2 the cartridge retention member 808 may passstraight into the passage 316 to position 6, whereas at position 1 thefirst guide member 312 inflicts a turning of the cartridge retentionmember, starting at position 4, where the cartridge retention memberlands on the first guide member and continuing by the inflicted turningand longitudinal movement such that it is guided into the passage 316.Also at position 3 on the other side of the passage 316, a first guidemember 312 inflicts a turning of the cartridge retention member,starting at position 5, where the cartridge retention member lands onthe first guide member and continuing by the inflicted turning andlongitudinal movement such that it is guided into the passage 316. Thus,substantially irrespective of the angle at which the cartridge retentionmember is received, it is guided into the passage 316.

Continuing its journey from a position, such as position 6, in thepassage, in the receiving direction, the cartridge retention memberlands on a second guide member 322 of the second section 330 and inparticular on a first section 344 thereof. Due to the inclined face ofthe first section 344, a turning of the cartridge retention member 808is inflicted, such that the cartridge retention member 808 turns fromposition 7 to position 8, where it meets one of the first riser portions340 which prevents further rotation. At this position, a user insertingthe cartridge assembly will feel that the cartridge assembly stopsmoving, and will therefore intuitively release the force used forinsertion. At this position 8, a release of the force will make thespring-loaded ejector push the cartridge assembly and the cartridgeretention member 808 outwards, opposite the receiving direction, toposition 9. At position 9 the cartridge retention member 808 lands onthe slope portion 334 of a first guide member 312 leading towards theretention portion 328 at or about a bottom portion of the concave shapeat a retention angle 332. Due to the spring-loaded ejector working topush the cartridge retention member 808 outwards, the cartridgeretention member 808 and hence the cartridge stays in a retentionposition, position 10.

It should be noted that as the cartridge retention member travels outover the second riser portion 342, it passes a point of no return andthe inbound journey is generally not reversible. So, should the userease the force used for insertion before position 8, but after the pointof no return, the cartridge still ends up in the retention position.

While in the retention position the cartridge and the cartridge assemblymay be prevented from moving in the receiving direction by a lock thatintroduces a stop. Thereby the cartridge stays in its retention positioneven if a force overcoming the spring-load on the cartridge or cartridgeassembly is overcome e.g. while the needle penetrates the skin. When thelock is released again to remove the stop, an outbound journey canstart.

An outbound journey starts out from position 10 and is initiated whenthe spring-loaded force is overcome in the receiving direction, e.g. bya user pressing on a needle cover of the cartridge assembly. Thecartridge retention member then lands on the second face 326 (cf. FIG.10) and in particular a first section 344 thereof at position 808-11.Therefrom, it is brought to position 12. At this position, a userejecting the cartridge assembly will feel that the cartridge assemblystops moving, since the cartridge retention member 808 meets a firstriser portion 340, and will therefore intuitively release the force usedfor ejecting the cartridge assembly. In releasing the force, thespring-loaded ejector will push the cartridge assembly and the cartridgeretention member 808 outwards, opposite the receiving direction, toposition 13, where the cartridge retention member 808 meets an ejectface 338 that guides the cartridge retention member 808 towards aposition 14 in the passage 316 and onwards to a position 15 where thecartridge assembly is fully ejected and can be handled as needed e.g. toremove the cartridge from the cartridge assembly and dispose thecartridge.

It is noted that the direction of rotation, DR, is defined by thedirection of the slopes of the first face and second face since theydefine in which direction turning is inflicted.

With respect to the length of an ejector rod 202 and the length ofejector cogs 226 thereof, to be explained in greater detail furtherbelow, it is noted that the cartridge retention member 808 should beallowed to travel between a first and a second extreme positions, L1 andL2, spaced apart at a longitudinal distance L12. At the position L2, thecartridge retention member 808 is at its retention position, i.e. anadvanced position towards the cartridge receiver opening. At theposition L1, the cartridge retention member 808 is at a ‘deepest’position, in the receiving direction, given by the second face 326 orsection 346 thereof. Thus, the ejector should be able to travel thedistance L12. In some embodiments the position L3 may be located at a‘deeper’ position than L1, in which case the ejector should allow thecartridge assembly retention member 808 to travel between L3 and L2.

FIG. 9a is a cross-sectional view of the first section of the cartridgereceiver compartment. This cross-sectional view is orthogonal to thelongitudinal axis and shows first guide member angles 314 and passageangles 318 that extend over the first guide members 312 and the passage316, respectively. The outwardly pointing apex of the first guidemembers is shown at a centre angle of the first guide member angles 314.The first bore is indicated by reference numeral 320.

The arrow designated by capital ‘R’ indicates a radial axis orthogonalto the longitudinal axis.

FIG. 9b is a cross-sectional view of the second section of the cartridgereceiver compartment. This cross-sectional view is orthogonal to thelongitudinal axis and shows the first sections 344 and the secondsections 346 separated by first riser portions 340 and second riserportions 342.

Each of one of the first sections 344 and each of one of the secondsections 346 may extend over section angles. Section angles may by e.g.about 15 degrees.

FIG. 10 shows a detailed view of alternative first section and secondsection of the cartridge receiver compartment. The first guide members312 of the first section 310 have a concave shape with a slope 334 thatextends across the retention angle 332.

The second guide members 322 of the second section 330 comprises a firstface 324 that extends at least partly over passage angles 318 and firstguide member angles 314. A second face 326 extends between first faces,alternately. The first riser portions 340 separate the first faces 324and the second faces 326.

FIG. 11 shows an outer plunger rod. The outer plunger rod 404 iscomprised by the plunger 400 and has a plunger rod front end 410 with adimension that allows it to extend inside the cartridge to move astopper therein. The outer plunger rod 404 may be moved by an innerplunger rod (not shown) and the inner plunger rod and the outer plungerrod may be coupled by threading such that turning of the inner plungerrod inflicts a longitudinal movement of the outer plunger rod 404. Theouter plunger rod 404 may be retaining at an angle about thelongitudinal axis by means of a longitudinally extending plunger rodgroove 408 in the outer wall of the outer plunger rod.

The outer plunger rod 404 is configured with a plunger rod track 406.The track 406 may extend from the rim of the outer plunger rod at theother end than the plunger rod front end 410. The plunger rod track 406has at least one track portion 428 that leads an ejector lock guide pin216 (cf. FIG. 13) from a first angle to a second angle that areangularly spaced apart to turn an ejector lock 212 (cf. FIG. 13) fromthe first angular position to the second angular position. A secondtrack portion 432 extends from a plunger rod distal rim 424 along thelongitudinal axis, L, towards and to connect with the first trackportion 428 which is inclined with respect to the longitudinal axis e.g.at an angle of about 45°, e.g. about 30-45°, with respect to thelongitudinal axis, L. Thereby the second track portion 432 accommodatesthe ejector lock guide pin 216 when the outer plunger rod 404 is in aforward position, towards the cartridge receiver opening 301, to expel amedicament by moving the first stopper 708 in the first stopperdirection as mentioned above. When the second track portion 432accommodates the ejector lock guide pin 216, the ejector lock 212 isangularly positioned to prevent the ejector rod 202 from movingbackwards. A third track portion 430 connects with the first trackportion 428 and continues along the longitudinal axis towards theplunger rod front end 410. Thereby the third track portion 430accommodates the ejector lock guide pin 216 when the outer plunger rod404 is in a backward position, opposite the cartridge receiver opening301, whereat the outer plunger rod 404 is moved backwards, away from thefirst stopper 708. Thus, the longitudinal position of the outer plungerrod 404 has the dual function of:

-   -   engaging/disengaging with/from the first stopper 708 to expel        medicament or being withdrawn from the first stopper 708 to        forgo expel of medicament or removing the cartridge assembly        600; and    -   locking/unlocking the ejector rod 202 via rotation of the        ejector lock 212.

This is explained in greater detail below.

Thus, the outer plunger rod part 404 is configured with a plunger rodtrack 406 that engages with the ejector lock guide pin 216 and extendsfrom a plunger rod distal rim 424 towards plunger rod front end 410 andthus the cartridge receiver opening 301.

FIG. 12 shows an ejector and an ejector lock. The ejector is generallydesignated 200 and comprises an ejector rod 202. The ejector lock isconfigured to engage with the ejector rod by turning to therebyintroduce a stop that prevents the ejector rod 202 from moving in thereceiving direction.

The ejector rod has an ejector collar 224 arranged about an ejectorsupport face 204, which supports the cartridge at a cartridge back face716, which may have the form of a rim. The ejector rod 202 has anejector rod bore 222 to form a longitudinal passage all through theejector rod 202. The ejector rod bore 222 allows the outer plunger rod404 to move along the longitudinal axis.

The ejector rod 202 is configured with one or more ejector cut-outs 228to form one or more ejector cogs 226 between the ejector cut-outs 228.Complementary therewith, the ejector lock 212 is configured with one ormore ejector lock cogs 232 between one or more ejector lock cut-outs230, respectively. The ejector lock 212 is supported e.g. in a bearingthat allows the lock to turn or be turned, at least a fraction of arevolution, while preventing a longitudinal movement. The ejector lock212 may have a flange or a recess that engages with a complementaryrecess or protrusion, respectively, to maintain the ejector lock 212 ina fixed longitudinal position while allowing it to be turned at least afraction of a revolution. The ejector cut-outs 228 are also denotedejector slots 228.

As shown, the ejector lock 212 has an angular position such that theejector lock cogs 232 align with the ejector cut-outs 228. The ejectorrod 202 can thus move in the receiving direction until an end portion206 of the ejector cogs abuts a bottom portion 214 of the ejector lockcut-outs 230, since the ejector lock cogs 232 and the ejector cogs 226have substantially the same length. Thus, a bottom portion 214 of theejector lock cut-outs 230 abuts the end portion 206 of the ejector cogs226. The end portion 206 of the ejector rod 202 is also denoted anejector rest portion 206.

When the ejector lock 212 is turned such that ejector cogs 226 alignwith ejector lock cogs 232, a stop is introduced and the ejector rod 202is prevented from moving in the receiving direction. The stop isintroduced because, in that angular position of the ejector lock 212,the end portion 206 of the ejector rod 202 abuts the ejector locksupport portion 234 of the ejector lock 212. The ejector lock supportportion 234 of the ejector lock 212 is also denoted an ejector locksupport portion 234.

The ejector rod 202 may be prevented from turning, by means of an angleretaining guide 207 when it engages with an angle retaining slot 238(cf. FIG. 15), wherein the angle retaining slot 238 is arranged on or inthe cartridge receiver 300 or a member rigidly coupled to the cartridgereceiver 300.

FIG. 13 shows an ejector lock. The ejector lock 212 is shown in greaterdetail here. It can be seen that the ejector lock 212 is configured withan ejector lock bore 240 accepting at least an end portion of the outerplunger rod 404.

An ejector lock guide pin 216 sits in the ejector lock bore 240 andextends inwardly from a wall thereof.

FIG. 14a through 14d shows various positions of the ejector relative tothe ejector lock. In FIG. 14a the ejector rod 202 is shown in alongitudinal forward extreme position, relative to the ejector lock 212,where it is spring-biased to be when a cartridge assembly is notinserted through the cartridge receiver opening, e.g. as shown inFIG. 1. It can be seen that the ejector cogs 226 are aligned withejector lock cut-outs 230, although displaced far from each other, suchthat the stop is disengaged and the ejector rod 202 is thus allowed tomove to an extreme position in the receiving direction. Thereby theinbound journey and the outbound journey described in connection withFIG. 8b can take place during insertion or ejection of a cartridgeassembly.

In FIG. 14b the ejector rod 202 is shown in a longitudinal backwardextreme position e.g. when a cartridge assembly retention member 808 isin contact with the second section 330 of the retention mechanism. Thisposition of the cartridge assembly retention member 808 corresponds tothe position L1 or L3 shown in FIG. 8 b.

In FIG. 14c the ejector rod 202 is shown in a longitudinal positionwhere the cartridge assembly retention member 808 is in the retentionposition abutting the bottom of the concave shape of the first guidemember 312 of the first section 310. This position of the cartridgeassembly retention member 808 corresponds to the position L2 shown inFIG. 8 b.

In FIG. 14d the ejector rod 202 is shown in the same longitudinalposition as in FIG. 14c , but the ejector lock 212 is turned such thatthe stop is engaged. In this situation the ejector cogs 226 abuts theejector lock cogs 232 end-to-end. Thus, an end portion 206 of theejector cogs 226 abuts the end portion 234 of the ejector lock cogs 232.

Thus, at least both of the length of the ejector rod 202 and the lengthof the cogs and the cut-outs should be dimensioned to allow thecartridge assembly retention member 808 to travel between position L1and L2 and L3 and L2.

Thus, the elongated ejector 200 is suspended to move along thelongitudinal axis, L, and is enabled to move beyond a stop position 250(cf. FIG. 14b ) at a first angular position of ejector lock 212 and isprevented from moving beyond the stop position 250 by the ejector cogs226 abutting the ejector lock cogs 232 at a second angular position ofthe ejector lock 212 (cf. FIG. 14d ). At the first angular position ofejector lock, the elongated ejector is enabled to move beyond the stopposition, such as further until an extreme position 251 since theejector cogs enter the ejector lock cut-outs 230 between the ejectorlock cogs 232. In some aspects the ejector rod is a substantiallycylindrical rod coaxially arranged with the ejector lock, whichcomprises a substantially cylindrical portion.

FIG. 15 shows a cross section of an exemplary system comprising an autoinjector and a cartridge assembly. The cartridge assembly 600 comprisesa cartridge 700 with a cartridge compartment 702, a needle assembly 900,and a cartridge code feature 1000. The cartridge assembly 600 isreceived in the auto injector 4. The auto injector 4 comprises theejector rod 202 as described above. The ejector rod 202 is suspended forlongitudinal movement and is spring-loaded by an ejector spring 236which spring-loads the ejector rod 202 in the direction opposite of thereceiving direction. Thereby, during insertion of the cartridge assembly600, the spring force exercised by the ejector spring 236 has to beovercome to insert the cartridge assembly into a position where it isheld in a retention position.

The cartridge assembly 600 comprises a cartridge holder 800. Thecartridge holder 800 is configured for retention of the cartridge 700 inthe cartridge receiver 300 of the auto injector 4. The cartridge holder800 comprises a cartridge retention member 808. The cartridge retentionmember 808 engages with the cartridge receiver 300 for reception andretention of the cartridge 700 and the cartridge assembly 600 in thecartridge receiver 300.

The needle assembly 900 comprises a needle 902 and a needle hub 904. Theneedle assembly 900 is attached to the cartridge 700, e.g. by the needlehub 904 having a cartridge holder coupling portion 906, e.g. a threadedcoupling portion, being in engagement with a needle assembly couplingportion 812 of the cartridge holder 800. The needle 902 extends throughthe cartridge outlet 714 of the cartridge 700. The cartridge outlet 714may be blocked by a resilient sealing being penetrated by the needle902, when the needle assembly 900 is attached to the cartridge 700.

The auto injector 4 comprises a code sensor 24 configured to read thecartridge code feature 1000. When the cartridge assembly 600 isinserted, as shown, the cartridge code feature 1000 is lined up with thecode sensor 24.

The auto injector 4 comprises a plunger rod 400. The plunger rod 400 isconfigured to advance a first stopper of the cartridge 700. The plungerrod 400 comprises an outer plunger rod 404 with an inner thread, and aninner plunger rod 402 with an outer thread. The thread of the innerplunger rod 402 is in engagement with the thread of the outer plungerrod 404. The outer plunger rod 404 is prevented from rotating relativeto the housing of the auto injector. The movement of the plunger rod 400comprises rotation of the inner plunger rod 402. The rotation of theinner plunger rod 402 results in translational movement of the outerplunger rod 404, due to the outer plunger rod 404 being rotationallyrestricted. The outer plunger rod 404, when moved translationally in thefirst stopper direction 722, is configured to abut the first stopper ofthe cartridge 700, and to move the first stopper in the first stopperdirection 722.

The drive module 500 is coupled to actuate the plunger rod 400. Thedrive module 500 is electrically connected to a battery for receivingelectrical power. The drive module 500 comprises a motor 502, such as anelectro-mechanical motor, such as a DC motor. The drive module 500comprises a transmission 504 for coupling the motor 502 to the innerplunger rod 402 of the plunger rod 400.

The auto injector 4 comprises an ejection sensor 26, such as a plungerrod position sensor. The ejection sensor 26 is configured to detect theposition of the plunger rod 400. In the illustrated example, theejection sensor 26 comprises a tachometer configured to count/detect therevolutions of the motor 502. Thus, the position of the plunger rod 400may be determined based on the count of revolutions of the motor 502.The ejection sensor 26 may, based on the detection of the position ofthe plunger rod 400, detect the expelling of medicament and/or air inthe cartridge compartment. The position of the plunger rod 400 may beindicative of the position of the first stopper of the cartridge 700,e.g. the most advanced position of the plunger rod 400 during receptionof the cartridge 700 may be indicative of the position of the firststopper of the cartridge 700.

FIGS. 16a-d show cross sections of a portion of an exemplary systemcomprising an auto injector and a cartridge assembly. The auto injector4 comprises a cartridge receiver 300 configured for receiving andretaining a cartridge. The auto injector 4 comprises a contact member1102. The contact member 1102 may be movable between an extended contactmember position and a retracted contact member position. The contactmember 1102 comprises a contact member protruding part 1112. The contactmember protruding part 1112 is configured to move with the contactmember 1102. The contact member 1102 may be biased, e.g. by a contactmember spring (not shown), towards the extended contact member position.

The contact member comprises a needle cover engagement member 1114. Theneedle cover engagement member 1114 is configured to abut a needle coverabutment face, e.g. of a needle cover positioned on the cartridgeinserted into the cartridge receiver 300.

The auto injector 4 comprises a contact member sensor 1104 configured todetect a position of the contact member 1102. The contact member sensor1104 comprises a first contact member sensor 1130 and a second contactmember sensor 1132. The first contact member sensor 1130 and the secondcontact member sensor 1132 may be optical sensors. The contact membersensor 1104 detects the position of the contact member 1102 by thecontact member protruding part 1112 covering the first contact membersensor 1130 when the contact member 1102 is in a first contact memberposition, and the contact member protruding part 1112 covering thesecond contact member sensor 1110 when the contact member 1102 is in asecond contact member position.

The first contact member position may be detected by the first contactmember sensor 1130 being covered and the second contact member sensor1132 being covered. The second contact member position may be detectedby the first contact member sensor 1130 not being covered and the secondcontact member sensor 1132 being covered. The extended contact memberposition may be detected by the first contact member sensor 1130 notbeing covered and the second contact member sensor 1132 not beingcovered.

FIG. 16a schematically illustrates the auto injector 4 with no receivedcartridge and/or cartridge assembly. The contact member 1102 is in theextended contact member position. A cartridge may be inserted into thecartridge receiver 300 in the cartridge receiving direction 304 throughthe contact member 1102 defining a cartridge receiver opening 301.

FIG. 16b schematically illustrates the auto injector 4 with a cartridgeassembly 600 received. The cartridge assembly comprises a cartridge 700,a cartridge holder 800 and a needle assembly 900. The needle assemblycomprises a needle 902 and a needle cover 908. The needle cover has aneedle cover abutment face 910. The needle cover abutment face 910engages the needle cover engagement member 1114 of the contact member1102. The contact member 1102 is in the second contact member position,e.g. caused by the presence of the needle cover 908 and the abutment ofthe needle cover abutment face 910 on the needle cover engagement member1114. The contact member protruding part 1112 covers the second contactmember sensor 1132. The contact member protruding part 1112 does notcover the first contact member sensor 1130.

FIG. 16c schematically illustrates the auto injector 4 with a cartridgeassembly 600 received. Compared to FIG. 6b , the needle cover 908 hasbeen removed. The contact member 1102 is in the extended contact memberposition. The contact member 1102 is allowed to be moved to the extendedcontact member position since the needle cover abutment face 910 doesnot about the needle cover engagement member 1114. The contact memberprotruding part 1112 has moved with the contact member 1102. The contactmember protruding part 1112 does not cover the second contact membersensor 1132. The contact member protruding part 1112 does not cover thefirst contact member sensor 1130.

FIG. 16d schematically illustrates the auto injector 4 with a cartridgeassembly 600 received. The contact member 1102 is in the first contactmember position. The first contact member position may be the retractedcontact member position, or close to the retracted contact memberposition. The contact member 1102 may have been moved to the firstcontact member position by the contact member 1102 being pressed againstan injection site, thereby inserting the needle 902 into the injectionsite. The contact member protruding part 1112 has moved with the contactmember 1102. The contact member protruding part 1112 covers the firstcontact member sensor 1130.

The contact member protruding part 1112 covers the second contact membersensor 1132.

FIG. 17a-b shows various positions of the ejector relative to theejector lock in an embodiment where the cogs have inclined faces. InFIG. 17a the ejector rod 202 and the ejector lock 212 are in a mutualposition where the stop is engaged. However, it can be seen that theejector lock cogs 232 and the ejector cogs 226 have inclined endportions that abuts one another. Therefore, a further turning of theejector lock 212 by a few degrees or a fraction of a degree may move theejector 200 in the direction opposite of the receiving direction todisplace it up to and tightly against the cartridge or cartridgeassembly. Thereby, it is possible to reduce or eliminate clearances thatwould otherwise allow the cartridge to move slightly e.g. by as littleas a fraction of a millimetre, but that could cause an inaccurate dosebeing expelled. The amount of tightening force may be controlled e.g. bymonitoring current drawn by a motor coupled to drive the ejector lock.

In FIG. 17b the ejector 200 and the ejector lock 212 are in a mutualposition where the stop is disengaged. Bottom portions of the ejectorcut-outs 228 and/or the ejector lock cut-outs 230 may be inclined by thesame angle as the end portions of the cogs to match the cogs or, asshown, have a substantially flat bottom portion, substantiallyorthogonal to the longitudinal axis.

As a first item the auto injector may comprise an elongated ejector(200) that is configured with: an ejector support face (204) forsupporting the cartridge or cartridge assembly (600), a longitudinalejector slot (228) extending towards the ejector support face (204) froman ejector rest portion (206); wherein the elongated ejector (200) issuspended to move along the longitudinal direction and is spring-loadedin the direction opposite of the receiving direction; and an ejectorlock (212) supported for turning at least a fraction of a revolution andmaintained in a longitudinal position relative to the housing (6);wherein the ejector lock (212) has a ejector lock support portion (214)that is configured to align with and slide along the longitudinalejector slot (228) at a first angle and to be brought to align with theejector rest portion (206) at a second angle. The ejector slots 228 arealso denoted ejector cut-outs 228. The ejector rest portion 206 is alsodenoted an end portion 206 of the ejector rod 202.

As a second item, in accordance with the first item, the ejector (200)may comprise an ejector rod (202) with an ejector support face (204);wherein the ejector rod (202) has an ejector rod bore (222) to form alongitudinal passage, and wherein the ejector support face (204) isarranged at one end of the ejector rod (202) and has a disc shape or anannular shape.

As a third item, in accordance with the first item or second item, theejector rod (202) comprises an ejector collar (224) arranged about theejector support face (204).

As a fourth item, in accordance with any of the above items, the ejector(200) comprises an ejector rod (202) configured with one or more ejectorcut-outs (228) to form one or more ejector cogs (226) between theejector cut-outs (228); and wherein the ejector lock (212) is configuredwith one or more ejector lock cogs (232) between one or more ejectorlock cut-outs (230), respectively.

As a fifth item, in accordance with the fourth item, one or more of thecut-outs (230;228) and the cogs (232;226) have a substantiallyrectangular shape.

As a sixth item, in accordance with the fourth item, the one or morecut-outs (230;228) and the one or more cogs (232;226) comprises aportion that is inclined relative to the longitudinal axis and relativeto an axis orthogonal to the longitudinal axis.

As a seventh item, in accordance with the fourth item, ejector cogs(226) and lock cogs (232) comprise an end portion that is inclinedrelative to the longitudinal axis at an angle of less than 40 degrees orless than 30 degrees or less than 20 degrees relative to the orthogonalof the longitudinal axis.

As an eight item, in accordance with the fourth item, the ejector (200)comprises an ejector rod (202) configured with a substantiallycylindrical portion with one or more chamfers about the longitudinalaxis to form a rotational asymmetric end portion; and wherein theejector lock (212) is configured with one or more complementary chamfercuts to form a complementary rotational asymmetric end portion.

As a ninth item, in accordance with any one of the above items, the autoinjector comprises a plunger rod (400); wherein the ejector (200)comprises an ejector rod (202) which is spring-loaded by a springejector member (236); wherein the plunger rod (400) and the bore areconfigured for longitudinal relative movement.

As a tenth item, in accordance with the ninth item, the plunger rod(400) comprises an inner plunger rod part (402) and an outer plunger rodpart (404); wherein the inner plunger rod part (402) and the outerplunger rod part (404) are coupled by a thread; wherein the innerplunger part (402) is retained in a bearing allowing rotation of theinner plunger part (402) while preventing a longitudinal movement; andwherein the outer plunger rod part (404) is retained in an angularposition relative to the housing (6).

As an eleventh item, in accordance with the tenth item, the autoinjector comprises an angle retaining slot (238) and an angle retainingguide (207) configured to engage with each other and arranged on or inthe cartridge receiver (300) or a member rigidly coupled to thecartridge receiver (300) and at the ejector rod (202).

As a twelfth item, in accordance with any one of the above items, theejector lock (212) comprises an ejector lock guide pin (216) configuredto engage with a plunger rod track (432) provided in the plunger rod(400), such that longitudinal movement of the plunger rod (400), atleast over a predefined range, inflicts a turning of the ejector lock(212) about the longitudinal axis (L).

As an thirteenth item, in accordance with the twelfth item, movement ofthe plunger rod (400) in the receiving direction, at least over a rangeof longitudinal positions, inflicts a turning of the ejector lock (212)to the first angular position.

As a fourteenth item, in accordance with the twelfth item, the ejectorlock (212) is configured with an ejector lock bore (240) to accept atleast an end portion of the outer plunger rod (404) and an ejector lockguide pin (216) that extends inwardly from a wall of the ejector lockbore (240); wherein the outer plunger rod (404) is configured with aplunger rod track (406) that engages with the ejector lock guide pin(216) and extends from a plunger rod distal rim (424) towards thecartridge receiver opening (301); wherein the plunger rod track (406)has at least one track portion that leads the ejector lock guide pin(216) from a first angle to a second angle that are angularly spacedapart to turn the ejector lock (212) from the first angular position tothe second angular position.

As a fifteenth item, in accordance with the twelfth item, the plungerrod track (406) is configured as a recess that extends from the plungerrod distal rim (424) of the outer plunger rod (404).

As a sixteenth item, in accordance with any one of the above items, theejector lock (212) is coupled to a resilient member that biases theejector lock towards the second angular position.

As a seventeenth item, in accordance with any one of the above items,the auto injector comprises a drive module with a motor and one or moreof transmission and gearing to couple the motor to the inner plungerrod.

As an eight item, there is provided an auto injector (4) foradministering injection of a medicament from a cartridge (700)containing the medicament, the auto injector comprising: a housing (6);and a cartridge receiver (300) with a cartridge receiver compartment(302) configured to receive a cartridge assembly (600) with at least onecartridge retention member (808) when inserted through a cartridgereceiver opening (301) along a longitudinal axis; and an ejector (200)configured to support the cartridge assembly (600) by being suspended tomove along the longitudinal direction and being spring-loaded in thedirection opposite of the receiving direction; wherein the cartridgereceiver compartment (302) has a first section (310), at a firstdistance from the cartridge receiver opening (301), with inwardlyextending first guide members (312) that extends over first guide memberangles (314) and are spaced apart to form a passage (316) at passageangles (318) between the inward first guide members (312); wherein theinward first guide members (312) form a first bore (320) accepting thecartridge assembly (600) when inserted through the cartridge receiveropening (301); wherein the cartridge receiver compartment (302) has asecond section (330) with an annular shape, at a second distance fromthe cartridge receiver opening (301), and with second guide members(322) with first faces (324) that are inclined about a radial axis tothe longitudinal axis and angularly arranged to extend at least partlyover passage angles (318) and first guide member angles (314).

As a ninth item, in accordance with the above item eight there isprovided an auto injector, wherein one or more of the first guidemembers (312) has/have a face that faces away from the cartridgereceiver opening (302) and forms a concave shape with a slope portion(334), at slope angles (336), leading towards a retention portion (328)at or about a bottom portion of the concave shape.

As a tenth item, in accordance with the above item eight or nine thereis provided an auto injector, wherein the second guide member (322) hassecond faces (326) that are inclined about a radial axis to thelongitudinal axis and are arranged alternately with the first faces(324); wherein the first faces (324) and the second faces (326) areinclined towards greater distance from the cartridge receiver opening(301) in a direction of rotation being either a clockwise oranticlockwise direction; wherein the first faces (324) and the secondfaces (326) are separated by first riser portions (340); and wherein thefirst riser portions (340) are angularly positioned at or within thefirst guide member angles (314).

Other aspects of the items above are set out in the claims and in thepresent specification.

The invention claimed is:
 1. An auto injector for administering aninjection of a medicament from a cartridge containing the medicament,the auto injector comprising: a housing; and a cartridge receiver with acartridge receiver compartment configured to receive a cartridgeassembly with at least one cartridge retention member when insertedthrough a cartridge receiver opening along a longitudinal axis; and anejector configured to support the cartridge assembly by being suspendedto move along the longitudinal direction and being spring-loaded in thedirection opposite of the receiving direction; wherein the cartridgereceiver compartment has a first section, at a first distance from thecartridge receiver opening, with inwardly extending first guide membersthat extend over first guide member angles and are spaced apart to forma passage at passage angles between the inward first guide members;wherein the inward first guide members form a first bore accepting thecartridge assembly when inserted through the cartridge receiver opening;wherein one or more of the first guide members has a face that facesaway from the cartridge receiver opening and forms a concave shape witha slope portion, at slope angles, leading towards a retention portion ator about a bottom portion of the concave shape; wherein the cartridgereceiver compartment has a second section with an annular shape, at asecond distance from the cartridge receiver opening, and with secondguide members with first faces that are inclined about a radial axis tothe longitudinal axis and angularly arranged to extend at least partlyover passage angles and first guide member angles; wherein the secondguide member has second faces that are inclined about a radial axis tothe longitudinal axis and are arranged alternately with the first faces;wherein the first faces and the second faces are inclined towards agreater distance from the cartridge receiver opening in a direction ofrotation being either a clockwise or anticlockwise direction; whereinthe first faces and the second faces are separated by first riserportions; and wherein the first riser portions are angularly positionedat or within the first guide member angles.
 2. The auto injectoraccording to claim 1, wherein the first guide members have a first guideface that faces the cartridge receiver opening and forms a convexpointing shape with an apex directed towards the cartridge receiveropening.
 3. The auto injector according to claim 1, wherein the firstsection and the second section maintains a fixed angular position withrespect to each other.
 4. The auto injector according to claim 1,wherein the first section and the second section are integrally formedwith the cartridge receiver to form a single piece.
 5. The auto injectoraccording to claim 3, wherein one or more first riser portions areangularly arranged at slope angles; and wherein one or more first riserportions are angularly arranged between the retention angle and a centreof passage angles in a direction of rotation being either a clockwise oranticlockwise direction.
 6. The auto injector according to claim 4,wherein one or more of the first faces and the second faces are dividedinto sections separated by a second riser portion.
 7. The auto injectoraccording to claim 5, wherein a first guiding member has an eject facethat is inclined towards the cartridge receiver opening at angles beyondthe retention angle in a direction of rotation being either a clockwiseor anticlockwise direction.
 8. The auto injector according to claim 1,wherein the second guide members are configured as a first set of stepswith treads that are inclined about the radial axis and a second set ofsteps with treads that are inclined about the radial axis; wherein thetreads of the first and second steps are inclined towards greaterdistance from the cartridge receiver opening for a clockwise oranticlockwise direction of rotation; wherein the treads of the first setof steps are arranged more proximal to the cartridge receiver openingthan the treads of the second set of steps; and wherein the first set ofsteps are alternately arranged with the second set of steps; with riserportions between the steps, forming an annular member comprised by thesecond section.
 9. The auto injector according to claim 3, wherein theone or more first guide members and the second guide members areconfigured and angularly aligned such that: upon insertion, thecartridge retention member passes the passage in a longitudinaldirection, lands on a first section of the first face, by rotationfollows the first face out over a second riser portion to a secondsection, and upon ease of an insertion force, the cartridge retentionmember travels to the retention portion via the slope portion.
 10. Theauto injector according to claim 5, wherein the one or more first guidemembers and the second guide members are configured and angularlyaligned such that: upon release, the cartridge retention member leavesthe retention portion and lands on the first section of the second face,by rotation follows the second face out over a second riser portion to asecond section; and upon ease of a force, the cartridge retention membertravels to the eject face, wherefrom a the cartridge retention member isguided towards the cartridge receiver opening via a passage.
 11. Theauto injector according to claim 1, wherein the ejector comprises anejector lock that is operative by one or more of rotation, translationalmovement or axial movement to move to a position where movement of theejector is restricted in the direction of insertion.
 12. The autoinjector according to claim 1, wherein the elongated ejector isconfigured with: an ejector support face for supporting the cartridge orcartridge assembly, a longitudinal ejector slot extending towards theejector support face from an ejector rest portion; and an ejector locksupported for turning at least a fraction of a revolution and maintainedin a fixed longitudinal position relative to the housing; wherein theejector lock has a ejector lock support portion that is configured toalign with and slide along the longitudinal ejector slot at a firstangle and to be brought to align with the ejector rest portion at asecond angle.
 13. The auto injector according to claim 1, wherein theejector comprises an ejector rod configured with one or more ejectorcut-outs to form one or more ejector cogs between the ejector cut-outs;and wherein the ejector lock is configured with one or more ejector lockcogs between one or more ejector lock cut-outs, respectively.
 14. Theauto injector according to claim 13, wherein one or more of the cut-outsand the cogs have a substantially rectangular shape.
 15. The autoinjector according to claim 1, comprising a plunger rod operative bymovement along the longitudinal axis to exercise a pressing force on acartridge accommodated in the cartridge assembly.
 16. The auto injectoraccording to claim 15, wherein the plunger rod is accommodated in theejector to be longitudinally displaceable.
 17. The auto injectoraccording to claim 15, wherein the ejector lock comprises an ejectorlock guide pin configured to engage with a plunger rod track provided inthe plunger rod, such that longitudinal movement of the plunger rod, atleast over a predefined range, inflicts a turning of the ejector lockabout the longitudinal axis.
 18. The auto injector according to claim17, wherein the plunger rod track comprises at least one track portionthat guides the ejector lock guide pin from a first angle to a second toturn an ejector lock from the first angular position to the secondangular position.
 19. The auto injector according to claim 1 comprisingan operational module configured to: engage the plunger rod to movealong the longitudinal axis to exercise a pressing force on a cartridgeaccommodated in the cartridge assembly; and engage an ejector lock byone or more of rotation, translational movement or axial movement tomove to a position where movement of the ejector is restricted in thedirection of insertion.